无压浸渗法制备氧化态SiC颗粒增强铝基复合材料

Fabrication of Oxidized SiC Particles Reinforced Aluminum Matrix Composite by Pressureless Infiltration Technique

研究了SiC颗粒在1000~1200℃的氧化行为,其氧化增重率与保温时间符合抛物线规律,氧化增重受扩散过程控制,氧化激活能为219 kJ/mol.采用预氧化处理的SiC颗粒为增强体,含Si、Mg的铝合金为基体,通过无压浸渗方法制备了SiCp/Al复合材料,分析了复合材料的微观组织与界面形貌,探讨了无压浸渗机理.复合材料中颗粒分布均匀,无偏聚现象.材料制备过程中存在界面反应,SiC颗粒表面的氧化层与铝合金中的Mg、Al反应形成了一定数量的MgAl2O4.界面反应的存在提高了润湿性,促进了无压自发浸渗.

The oxidation behavior of SiC particles in the temperature range from 1000℃ to 1200℃ was investi-gated.The dependence of weight gain and oxidation time was parabolic and the oxidation behavior was controlled by diffusion process,with a oxidation activation energy of 219 kJ/mol.Using oxidized SiC particles as reinforce-ment and aluminum alloy containing Si and Mg as matrix,a SiCp/Al composite was fabricated by pressureless infil-tration technique.The microstructure and interfacial morphology were analyzed and the pressureless infiltration mechanisms were discussed.The particles were distributed uniformly in the composite,without particles agglom-eration.Interfacial reactions were found in the composite and the product was identified as MgAl2O4,formed by the reactions between surface oxide layer of SiC particles and Mg,Al in the matrix.The interfacial reactions enhanced the wettability and promoted the spontaneous infiltration process.